7a cam timing

[Audi_CQ]

hi roger,is my set up suitable for the 7a cams im running 3b standard lump rs2 ex..rs2 turbo .....the rest standard.............. the valve timing/ ignition ...standard..........?

A RS2 turbo is good for ~360 and max out at ~5k so not much use for the 7A intake cam. Since the RS2 ex. manifold is better then the S2 the 7A ex. cam can help a bit more and give better spool, but don't expect miracles

[Jamo]

I'm also sorry to go off topic , but my intension was just to make people think for themself and not just believe everything that's written on the web
I often ask myself WHY? when reading on forums.

First to try to answer your question
If your engine is stock or just chipped, don't use 7A cams. If further mods are planned try this:
If using std parts set cams on std marks.
If using 7A cams with adjustable cam pulley, try to set them 5 degrees adv.
If fully adjustable "chainwheels" is used set ex 5 deg adv , and inlet at std timing.


In this case of 7A cams you get a lot of different answers. Why? Different engine setups give different results. You always has to find the weakest link in your setup. If cams isn't the weakest link you get little or nothing out of changing cams.

In a stock/near stock(chipped) engine the weakest link on the exhaust side is the restrictive EM and turbo. Since they create a lot of backpressure you have to use cams with little or no overlap to avoid exhaust blowing into intake at overlap. 7A ex. cam has the same cam timing as std cam, just more lift, so doesn't harm. Very little gain so if not planning for further mods I wouldn't change it.

On inlet side the problem is again the turbo. It just doesn't have a lot of capasity, and when the turbo can't deliver anymore it doesn't help what intake cam you use. Turbo is maxed out anyway. Limit is about 270-290 real hp on a chipped but otherwise stock engine. The turbo will be empty long before you get to the kind of RPM where the 7A inlet will help out (~5k) so no use for the extra duration here so stay with the std inlet.

Just my 0.02$

Cheers,
Roger

Interesting, do you run this setup?

[repo]

I 100% backup cq's writeup.

I would not change stock ones unless really going to well over 500hp, if we are talking about a street car.

[GazzaG60]

although i have a fairly modified setup and i recently installed a 7a ex cam i am soon to go back i think.

i wouldn't so much say lag but id expect overlap that creates the effect of lag. i get spool as early but it doesn't pull as hard. question is can we phase the cams using adjustable wheels enough to get the required results. id expec so but am yet to prove it.

i tend to believe this in general is the secret HP area of tuning and its hard to get the real answers on that.

any ideas. anybody set overlap to 10-12 deg? results?

[Bram]

I 100% backup cq's writeup.

I would not change stock ones unless really going to well over 500hp, if we are talking about a street car.

Would it make sense to switch from stock to ADU cams, when running a GT3071R?

[GazzaG60]

mines bigger than a 3071R so i doubt it. stich with stock for the road otherwise wildlife will overtake you off boost.

[Audi_CQ]

Interesting, do you run this setup?

No, I went for the full package and are now running mech cams.
I've used 7A cams earlier in my 2.5 with success(both 5 degrees advanced) and have a friend with a 2.2 who have converted his 7A cams to be fully adjustable. Testing on this engine showed that advancing ex cam 5 degrees would get a bit faster spoolup with same top end power.

About cams in std or near std engines it's just my 0.02$ based other peoples testing and what I've read on backpressure problems and the compressor capacity of K24 turbo's.

[Bram]

mines bigger than a 3071R so i doubt it. stich with stock for the road otherwise wildlife will overtake you off boost.

ok, but you are running 7A, while I asked if ADU cams would be any good with my turbo instead of the 7As. I mean, the ADU cams are from the RS2 which is a daily drivers car as well, so they should not be much worse then the S2 cams I guess? They just give a bit more lift and are 10 degrees advanced compared to stock S2 cams

[newsh]

I know of one car running RS2 cams with a 3071 which is a real screamer.

I have recently gone back to stock Ex cam from the 7A, although the top end is really nice on the 7A (Mihnea mapped my car with this cam in place) I was bored with having to keep the revs above 3k to get any kind of go out of it.

[Bram]

I know of one car running RS2 cams with a 3071 which is a real screamer.

whohoo! finally somebody knowing somebody with the same setup like me! Do you have more info from this setup and performance?

I have to say my car goes like crazy once the boost builds up and pulls straight on to the revv limit, without having the feeling that the car loses some punch in the top revv's. But then again I presume 7A would add a little bit more steam up the revv-line

When I read more and more that people find the low-end with the 7A ex cam too soft I tend to stick with the ADU cams.....

[A80Avant]

bram,my car is ADU with ADU cams,and 3071R all along...

[Bram]

bram,my car is ADU with ADU cams,and 3071R all along...

Yes, sorry Papvas. I did not forget you
However you were still in doubt about your rolling road results from Greece, so another GT3071R 0.63 with ADU cams would be an interesting comparison.

I am planning to go to a RR within 1 month. My new house is about be finished, so I can spend time on the S2 again

[newsh]

Bram, I will try to find out if there is a dyno plot for the car.

[Bram]

Bram, I will try to find out if there is a dyno plot for the car.

Thanks! Do you happen to know what modifications were done to the engine? porting? uprated clutch, etc....

[A80Avant]

any recommendations for a respectable dyno area on the North east to have a go here??